Low Pressure Drop Fin with Selective Micro Surface Enhancement
The assembly includes a heat exchanger assembly including a plurality of tubes extending between first and second manifolds. A plurality of fins extend back and forth between and long the tubes in a continuous patch and define a plurality of legs extending between the tubes. Each of the legs includes a plurality of front long louvers for conveying a stream of air through the legs. Each of the legs further defines a plurality of main spoilers between the front long louvers and the back edges of the legs for inducing turbulence in the stream of air with each of the main spoilers having a spoiler height in the range of 50 to 90 percent of the long louver height and each of the main spoilers having a spoiler length in the range of 10 to 35 percent of the long louver length.
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1. Field of the Invention
A heat exchanger assembly, and more specifically, a heat exchanger assembly including louvered air fins for transferring heat between a refrigerant and a stream of air.
2. Description of the Prior Art
A vast number of heat transfer applications, e.g. residential HVAC, electronics, etc., operate under very low thermal heat transfer potential. In other words, the temperature difference between the refrigerant and the stream of air entering the heat exchanger is not great. Additionally, the size and power of the fan propelling the stream of air through a heat exchanger is often limited by a number of constraints, e.g. power usage, noise, space, etc. For example, in a laptop computer, the size of the fan must be minimized to fit within the space constraints of the casing, and the power of the fan must be minimized to avoid draining the battery or producing undesirable noise. In these applications, the performance of the air fins in transferring heat between the refrigerant and the stream of air is critical. Air fins generally include louvers to increase heat transfer, but those louvers also create an undesirable pressure drop in the stream of air.
U.S. Patent Application Publication No. 2008/0121385, to In Chuil Kim (hereinafter referred to as Kim '385) shows a heat exchanger assembly for transferring heat between a refrigerant and a stream of air. Kim '385 includes first and second manifolds spaced from one another. A plurality of tubes extend in spaced relationship with one another between the first and second manifolds for conveying the refrigerant between the first and second manifolds. A plurality of fins are disposed between adjacent tubes for transferring heat between the tubes and the stream of air. Each of the fins has a front edge and a back edge and presents a plurality of legs extending transversely between the adjacent tubes. Each of the legs of the fins defines a plurality of front long louvers disposed between the front and back edges for conveying the stream of air through the legs of the air fins with each of the long louvers having a long louver height and a long louver length.
SUMMARY OF THE INVENTION AND ADVANTAGESThe invention provides for such a heat exchanger assembly and wherein each of the legs of the fins defines a plurality of main spoilers disposed between the front long louvers and the back edges for inducing turbulence in the stream of air with each of the main spoilers having a spoiler height in the range of 50 to 90 percent of the long louver height and each of the main spoilers having a spoiler length in the range of 10 to 35 percent of the long louver length.
The potential for heat transfer between the refrigerant and the stream of air decreases as the air flows downstream through the heat exchanger because the temperature difference between the refrigerant and the stream of air is reduced. The long louvers have more potential for heat transfer than the main spoilers because the long louvers turn and induce turbulence to the stream of air, whereas the main spoilers function mainly to induce turbulence in the air. Therefore, the long louvers are disposed upstream, where the temperature difference between the stream of air and the refrigerant is greatest, of the main spoilers. The upstream long louvers perform the majority of the heat transfer between the stream of air and the refrigerant. Although long louvers are very effective at transferring heat between the stream of air and the refrigerant, they come at a cost. Namely, long louvers create a large pressure drop in the stream of air flowing through the heat exchanger. Therefore, it is undesirable to have long louvers extend the entire length of the air fin. The smaller main spoilers are disposed downstream of the long louvers to induce turbulence in the stream of air to increase the air's heat transfer potential without compromising the overall pressure drop of the heat exchanger. This allows for a greater quantity of air to flow through the upstream long louvers of the fins and improves the overall efficiency of the heat exchanger assembly.
Other advantages of the present invention will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a heat exchanger assembly 20 for transferring heat between a refrigerant and a stream of air 22 is generally shown in
Referring to
A plurality of fins 42, generally indicated, are disposed between adjacent ones of the tubes 32 for transferring heat between the refrigerant in the fluid passages 40 of the tubes 32 and the stream of air 22. The fins 42 have a fin height HF. The fins 42 extend continuously between a front edge 44 adjacent to the round front 36 of the tubes 32 and back edge 46 adjacent to the round back 38 of the tubes 32. In other words, the front edge 44 of the fins 42 is upstream of the back edge 46 of the fins 42. Each of the fins 42 includes a plurality of legs 48 extending transversely between the adjacent tubes 32. The fins 42 also include a plurality of end portions 50 engaging the flat sides 34 of the adjacent tubes 32. Together, the legs 48 and end portions 50 of the fins 42 present a serpentine path extending between the first and second manifolds 24, 26. In other words, adjacent legs 48 of the fins 42 are connected by end portions 50 engaging opposite ones of the flat sides 34 of the adjacent tubes 32.
In all of the embodiments of the subject invention, shown in
In all of the embodiments of the subject invention, shown in
As shown in
In the first embodiment, shown in
The second embodiment, shown in
The third embodiment, shown in
Like the third embodiment, the fourth embodiment, shown in
The fifth embodiment, shown in
The sixth embodiment, shown in
It should be appreciated that the main spoilers 56, 58, 60 may take any number of shapes, not just those shown in
In applications where the maximum thermal potential for total heat dissipation is small, it is paramount that total airflow through the heat exchanger assembly 20 be high. With fan power and noise constraints, airflow can be high only when the overall pressure drop of the heat exchanger is kept to a minimum. Having front spoilers 64, as shown in
As shown in
While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
Claims
1. A heat exchanger assembly for transferring heat between a refrigerant and a stream of air, comprising:
- a first manifold;
- a second manifold spaced from said first manifold;
- a plurality of tubes extending in spaced relationship with one another between said first and second manifolds for conveying the refrigerant between said first and second manifolds;
- a plurality of fins disposed between adjacent ones of said tubes for transferring heat between the refrigerant in said tubes and the stream of air;
- each of said fins having a front edge and a back edge and including a plurality of legs extending transversely between said adjacent tubes;
- each of said legs of said fins defining a plurality of front long louvers disposed between said front and back edges for conveying the stream of air through said legs of said air fins with each of said long louvers having a long louver height and a long louver length; and
- each of said legs of said fins defining a plurality of main spoilers disposed between said front long louvers and said back edges for inducing turbulence in the stream of air with each of said main spoilers having a spoiler height in the range of 50 to 90 percent of said long louver height and each of said main spoilers having a spoiler length in the range of 10 to 35 percent of said long louver length.
2. The assembly as set forth in claim 1 wherein said main spoilers are micro-louvers.
3. The assembly as set forth in claim 1 wherein each of said legs of said air fins presents a plurality of front spoilers disposed between said front edge and said front long louvers for inducing turbulence in the stream of air.
4. The assembly as set forth in claim 3 wherein each of said front spoilers extends outwardly from said legs and has a triangular shape.
5. The assembly as set forth in claim 3 wherein each of said legs of said air fins defines a plurality of back spoilers disposed adjacent to said back edge and a plurality of back long louvers disposed between said micro-louvers and said back spoilers.
6. The assembly as set forth in claim 1 wherein each of said legs of said fins has a fin height and said long louver height is in the range of 50 to 90 percent of said fin height.
7. The assembly as set forth in claim 1 wherein said long louver length is in the range of 0.7 to 1.5 mm.
8. The assembly as set forth in claim 1 wherein said spoiler length is in the range of 0.15 to 0.4 mm.
9. The assembly as set forth in claim 1 wherein each of said front long louvers extends diagonally outwardly from said legs of said fins.
10. The assembly as set forth in claim 1 wherein said first and second manifolds extend in spaced and parallel relationship with one another.
11. The assembly as set forth in claim 10 wherein said first manifold defines a plurality of first tube slots spaced from one another and said second manifold defines a plurality of second tube slots spaced from one another and aligned with said first tube slots.
12. The assembly as set forth in claim 11 wherein each of said tubes has a cross-section presenting flat sides interconnected by a round front and a round back.
13. The assembly as set forth in claim 12 wherein said tubes extend in spaced and parallel relationship with one another between said aligned first and second tube slots of said first and second manifolds.
14. The assembly as set forth in claim 1 wherein each of said tubes defines a fluid passage for conveying the refrigerant between said manifolds.
15. The assembly as set forth in claim 1 where said main spoilers are disposed in a staggered arrangement.
16. The assembly as set forth in claim 1 wherein said main spoilers are semi-cylindrical bumps.
17. The assembly as set forth in claim 1 wherein said main spoilers are triangular notches.
18. A heat exchanger assembly for transferring heat between a refrigerant and a stream of air, comprising:
- a first manifold and a second manifold extending in spaced and parallel relationship with one another;
- said first manifold defining a plurality of first tube slots being spaced from each other;
- said second manifold defining a plurality of second tube slots being spaced from each other and aligned with said first tube slots;
- a plurality of tubes having a cross-section presenting flat sides interconnected by a round front and a round back and extending in spaced and parallel relationship with one another between said aligned first and second tube slots for establishing fluid communication between said first and second manifolds;
- each of said tubes defining a fluid passage for conveying the refrigerant between said manifolds;
- a plurality of fins disposed between adjacent ones of said tubes for transferring heat between the refrigerant in said fluid passages of said tubes and the stream of air;
- each of said fins including a plurality of legs with each leg having a fin height and each leg extending transversely between said adjacent tubes and each of said fins including a plurality of end portions extending along said flat sides of said adjacent tubes to present a serpentine path between said first and second manifolds;
- each of said legs of said fins having a front edge adjacent said round front of said tubes and a back edge adjacent said round back of said tubes;
- each of said legs of said fins presenting a plurality of front spoilers adjacent to said front edge and a plurality of back spoilers adjacent to said back edge for inducing turbulence in the stream of air;
- each of said front and back spoilers extending outwardly from said legs and having a conical shape;
- each of said legs of said fins presenting a plurality of front long louvers spaced from said front spoilers and a plurality of back long louvers spaced from said back spoilers for conveying the stream of air through said legs of said fins;
- each of said legs of said fins presenting a plurality of main spoilers disposed between said front long louvers and said back long louvers for inducing turbulence in the stream of air;
- each of said long louvers having a long louver height in the range of 60 to 90 percent of said fin height;
- each of said main spoilers having a spoiler height in the range of 50 to 90 percent of said long louver height;
- each of said long louvers having a long louver length in the range of 0.7 to 1.5 mm; and
- each of said main spoilers having a spoiler length in the range of 10 to 35 percent of said long louver length.
Type: Application
Filed: Dec 14, 2009
Publication Date: Jun 16, 2011
Applicant: Delphi Technologies, Inc. (Troy, MI)
Inventors: Debashis Ghosh (Williamsville, NY), James A. Acre (Barker, NY)
Application Number: 12/636,843
International Classification: F28F 1/12 (20060101); F28F 9/00 (20060101);